If you met could not open save as or open dialog box in windows 7,normally there are 4 possibilities. Please find below step the see detail.
If you only can not open save as or open dialog box in office 2007,please open Local Group Policy Editor and go to
User Configuration/Administrative Templates/Microsoft Office 2007 System / File Open / Save dialog box / Places Bar Locations
to check if your Places Bar Location [1-10] was set to the wrong value.
If your App can not open save as or open dialog box in Windowd 7,but it worked under Vista or Xp,you might need to use Program Compatibility troubleshooter to check if your app is compatible with Windows 7,if no,you can run it under compatible mode.
Please check if your computer have enough disk space or memory
If almost all of your Apps can not open save as or open dialog box,please try to Use Sfc Command To Repair System Files , or you might need to do a repair re-install of your windows 7